Rough idle that I can't get rid of

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Hi Guys,
I know this probably has a million threads on it but I can't find anything that I haven't tried to fix my problem. I bought an 04 BMW 330ci about 3 months ago that has 117,000 miles on it. I bought it needing a cyclone separator valve replacement and several codes on the computer which were lean conditions on both bank 1& 2, O2 sensor positive shorted on both banks as well. The idle was very erratic and you had to step on the gas to keep it running.

I replaced the cyclone separator valve and the idle got better but the lean codes were still there and the O2 sensor issues. I then replaced both pre-cat O2 sensors and found a small hole in the lower intake boot. I replaced the o-ring on the DISA valve the valve seems to be working without needing to be rebuilt. I then cleaned my MAF sensor and the idle control valve, it started to idle better but it lasted only a short time. I replaced the MAF sensor and now I don't get the lean codes on both banks and it started to idle normally for a short time plus the surging became less. I did a smoke test and didn't get any hits on anything so I rebuilt the VANOS system thinking due the age it had stiff o-rings. It idled well and no more surging for a short time that I ran the car.

The day after the VANOS rebuild, it started with a backfire and with a rough idle to the point it would stall if I didn't have my foot on the gas. I looked a the codes and then had 7 different codes. Missfire on several cylinders, lean bank codes on both banks, O2 positive shorted, crankshaft position sensor, but nothing on for the VANOS. I cleared the codes again and it ran normal with a decent idle (~400-500 rpm) but not great still a little rough.

The question I have is there anything that you guys think of that I'm missing or need to check/ replace because I am at a loss to why it still idles rough with no immediate codes but it has thrown codes for the O2 bank 1 & 2 positive circuit shorted that come and go. I have driven it over a 100 miles but still have to keep on the gas at idle or it sounds like it wants to die. Off idle the car runs strong no surging and gets good gas mileage.

[Hallatauer]

What did you do about the crank position sensor? You got a code for it so that may be the problem.

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It went away so I assumed it was just an intermittent error maybe caused from something else.

[Dave1027]

I'm thinking since the problem started after messing with the vanos it might be a ratty connection to an O2 sensor, cam sensor or vanos solenoid.